Optimizing the Design of Cluster Mill Rolling Bearings

Abstract

The design of back-up roll bearings in cluster-type rolling mills has, historically, been dictated by past engineering trial and error experience. Thus, to cause the bearings to act, as nearly as practicable, similarly to conventionally supported bearings, the outer ring section is usually made very heavy precluding large ring deflections. There exists controversy among bearing manufacturers as to whether a bearing having many rollers of small diameter or one having a smaller number of larger rollers is best in this application. The study herein presented examines bearing life under each condition while fully accounting for the effect of outer ring deflection on fatigue life. The investigation further demonstrates that an optimum design with regard to outer ring section thickness in relation to diametral size and number of rollers per row does exist with respect to bearing fatigue life. Whether such design is compatible with possible outer ring destruction due to heavy roll loads can only be proved by on-...